<?php
$s="计算机012ABC";
echo strlen($s),"\n";
$s="    \t\t   how are you ? \t\t \t";
echo "[$s]\n";
echo "[",trim($s),"]\n";
echo "[",ltrim($s),"]\n";
echo "[",rtrim($s),"]\n";

//
var_dump(strpos("how are you?","oo"));
if(strpos("how are you?","h")!==false){
    echo "find\n";
}else{
    echo "no find\n";
}

//
echo bin2hex("计算机012ABC"),"\n";

//
echo chunk_split("1234567",2,"*"),"\n";
//
echo str_replace("o","***","how are you?"),"\n";
//
echo '[',str_repeat("ok",3),"]\n";//[okokok]
echo '[',str_repeat("ok",0),"]\n";//[]
//
echo ord("ABCD");//显示ASCII码值 65
echo chr(65),"\n";
//
echo join(["hi","zhangsan","\n"]);
echo join(',',[123,456,789,"\n"]);
//
echo strtoupper("how are you?\n");
echo strtolower("how are you?\n");

//
